Formation treatment



May 9, 1967 r. D. BROWN FORMATION TREATMENT 2 Sheets-Sheetl 1 Filed April 7, 1964 F|G IB f TIMOTHY D. BROWN INVENTOR. W

FIG.

ATTORNEYS May 9 1967 T. D. BROWN FORMATION TREATMENT 2 Sheets-Sheet 2 Filed April 7, 1964 TIMOTHY D. BROWN 1N VENTOR.

AT TOR NE YS United States Patent Giliee 3,318,393 Patented May 9, 1967 3,318,393 FRMATION TREATMENT Timothy D. Brown, Houston, Tex., assignor to Halliburton Company, Duncan, kla., a corporation of Delaware Filed Apr. 7, 1964- Ser. No. 358,036 9 Claims. (Cl. 17S-4.52)

The present invention relates to the treatment of earth formations extending l-aterally of a borehole traversing such formation, and more particularly vto method and apparatus for performing formation treatment operations entailing the injection of materials thereint-o.

In order to produce a cased well, it is necessary to establish fluid communication between formation uids present in the pore space of the formation surrounding the well and the interior -of the casing in order that such formation fluid may be brought to surface through such casing. Such uid communication is usually provided by perforations penetrating the casing wall, cement sheath and the formation bearing the desired fluids. Normally such a simple completion procedure is satisfactory where the particles comprising the formation being produced are naturally adequately cemented together, however, where the formation being produced is incompetent or unconsolidated, as where the particles are unbonded or are inadequately bonded, production trouble of serious nature arises. The trouble is that loose particles of the formation are produced through the perforations into .the well bore to either cause serious problems of erosion and corrosion, or of choking the production from the wel-l due to accumulation ofdsuch particles therein.

One use aspect of the present invention is demonstrated in connection with the alleviation of these troubles and problems. In this connection the invention is employed to .force consolidating agents into Ithe incompetent formation beyond the perforation. These agents operate to cement or bind adjacent formation particles together whereby a local formation volume is transformed to a permeable mass of substantial strength and dimensional stability. The permeable mass, is, in effect, a filter constructed in situ which, in being located intermediate the unconsolidated formation and the production perforation, serves to block any unconsolidated formation particles which would otherwise be produced into the borehole along with t-he desired formation fluids.

Briey, the present invention enables effective and economical localized treatment of formation through a casing Wall for consolidation, or other purposes, eg., acidizing, involving some or all of the functions including isolating, perforating, puging, injection of one or more treating agents, and transient or other plugging.

An object of the present invention is the provision of a method for efliciently and effectively performing more or less complex formation treatments, such as sand consolidation, beyond the casing wall of the well bore.

Another object of the present invention is the provision of wireline apparatus of simple construction enabling such treatments to be reliably performed in accord with the method of the invention, some steps of the method being automatic and some at the hands of an oper-ator at .the earths surface.

Still another object of .the present invention is the provision of formation treating agent injection .apparatus producing a clean perforation by inducing an expulsive counter ow therefrom over a first path, and having a treating agent injection path to such perforation having a minimized portion in common with said first path.

A further object of the present invention is the provision of formation treating agent injection apparatus wherein any tendency toward plugging by perforation detritus is minimized.

A still further object of the present invention is the provision of formation treating agent injection apparatus including an injection path through which multiplle treating agents are sequentially passed, such that a subsequent agent in passing over said path is operative to effectively remove any residue of a preceding -agent from said path.

Another object of the present invention is the provision of a method of performing a number of adjacently spaced distinct formation treatments wit-hin a single formation zone whereby any influence on one such treatment due to an adjacent treatment is minimized.

yOther and further objects of the invention will be obvious upon the understanding of the illustrative matter about to be described or will be indicated in the appended claims, and variou-s advantages not referred to herein will occur to one skilled in the art upon the employment of the invention in practice.

Preferred forms of the invention have been chosen for purposes of illustration and description. These preferred forms are not intended to be exhaustive nor limit the invention to the precise forms disclosed. They are chosen and described in order to best explain the principles of the invention and their application in practical use to thereby enable others skilled in the art to best utilize the invention as may be best adapted to the particul-ar uses contemplated.

'In the accompanying drawings:

IFIGURE 1A is a partial sectional view illustrating, in a somewhat schematic manner, the upper portion of one form of apparatus of the invention and showing the same deployed in a cased well bore;

FIGURE 1B is a partial sectional view illustrating the lower portion of the apparatus of FIG. lA;

FIGURE 2 is a view partially showing the apparatus of FIG. 1B and showing elements thereof as they may be deployed during an intermediate stage of operation;

FIGURE 3 is a sectional view of a portion of the apparatus of FIG. lA, showing the sealing, per-forating and injection arrangement thereof in greater detail;

FIGURE 4 is -a sectional view, similar to FIG. 3, illustrating an alternate embodiment of the sealing, perforating and injection arrangement;

'FIGURE 5 is a sectional view, similar to FIG. 3, of stil-l another embodiment of the sealing, perforating and injection arrangement; and

FIGURE 6 is .a vertical sectional view taken laterally of a borehole and showing casing, cement sheath and earth formation, and illustrating, in a perhaps stylized manner, a perforation in the process of being provided therein.

Referring to the FIGURES 1A and 1B of the drawings, the apparatus of the invention comprises a body, generally designa-ted as 10, having been lowered by a wireline 11 within a well bore 13 traversing an earth formation to be treated. As shown, the well bore 113 is sheathed by a casing 14 `and an intermediate layer of cement 1S. The Iapparatus is shown in an actuated disposition in sealed anchored engagement with the casing wall adjacent a formation zone intended for treatment. Wireline 11 is provided with a central conductor 12 for communicating electrical signals from the surface f-or Iactuating various remotely controllable elements of the apparatus. The body 10 is generally comprised of an upper section 20, including components for actuation, anchoring, sealing, perforating and injection, together with elements for exerting general control over the operation of the apparatus; .and a lower section 70 which primarily functions .as a carrier of segregated treatment =agents for injection into the formation to be treated.

A hydraulic uid supply and pressure generator 22 is provided in the lower portion of upper section 20 for the purpose of supplying hydraulic fluid to a hydraulic actuation system at a pressure higher than the pressure of fluids normally present within the borehole. Although the pressure generator 22 may be of any suitable type, where it is desired to utilize the hydrostatic pressure energy of a borehole fluid as a source of power, a differential pressure type of generator, including remote control valves to control the same, such as is disclosed by Chambers in Patent No. 2,674,313 may be preferred. This type of pressure generator is adapted to produce .the required pressurized fluid pursuant to a rst electrical signal transmitted from the earths surface, and to dump andV relieve the pressure in the hydraulic actuation sys- Vtem pursuant to a second electrical signal transmitted from` the earths surface. l

The output of hydraulic pressure generator 22 is connected to the hydraulic actuation system including pistoncylinder type upper and lower actuator elements, 24 and 25 respectively, by means of a fluid passageway 26. The actuator elements 24 and 25 lmay identically comprise a cylinder-like concavity 28 in body 10 receiving a plunger 29 which extends in sealed slidable engagement with and laterally of the body 10. Although the plungers 29 are shown extended in FIG. 1A, they are normally maintained in a retracted position in their respective concavities 28 by suitable bias provided by springs 30. With this arrangement, the actuator elements 24 and 25 are adapted to extend their respective plungers 29 toward the borehole wall in response to pressurized hydraulic fluid being supplied via passageway 26 from the pressure generator 22, and to retract into their respective concavities 28 in response to bias of springs 30 acting with the pressure of borehole uid acting on the distal ends thereofV when the actuating fluid pressure is removed during the dump cycle of the pressure generator 22 The function of the actuators 24 and 2S is to extend laterally of the body to engage a wall portion of the casing 14, and, thereupon, move the body 10 laterally .in an opposite direction to force a sidewall sealing assembly 33 into sealing engagement with an oppositely disposed casing wall portion to accomplish isolation of a casing wall portion fromthe general fluid environment of the borehole. The distal ends of the plungers 29 are provided with hardened serrated surfaces 31 which are adapted to cut into the casing w-all when urged thereagainst, to thereby accomplish an effective anchoring of the body 10 and prevent any shifting of the same in the casing during the remainder of `the operation sequence to be described hereinafter.

As illustrated, actuator elements 24 and 25 are spaced apart along the body 10 in vertically straddling and opposed relation to the sidewall sealing assembly 33. Within the space thus provided between the actuator elements, there is provided a chamber 40 which functions as a carrier space for an explosive perforator element, such as the shaped charge 41 and metallic liner 42 illustrated, as well as functioning to provide a local fluid environment of controlled or predictable character, insofar as pressure and kinematic viscosity properties thereof are concerned, upon the firing of the explosive charge 41.

Sidewall sealing assembly 33 is comprised of an annular sealing element 34-of rubber-like material, and a port plug 35 which extends in sealed relation through the body 10 into the chamber 40. The portion of the port plug 35 which extends within the chamber 40 is configured to receive the conically concave lined end of charge 41 to position the same so that the jet or perforating axis thereof, i.e., the axis of the concave end, coincides with the axis of a perforating passageway 36 in the port plug 35. A thin wall 37 normally closes the perforating passageway 36, but is adapted to be easily breached by the jet, comprised of a metallic liner 42, when the same, projected from the chamber 40 upon the firing of the charge.

Referring'now to FIG. 3, wherein sidewall sealing assembly 33 is shown in greater detail, port plug 35 is seen to be comprised of a flange-like element 35A to which the annular sealing element 34 is attached, as by vulcanization, and a port plug per se 35B which extends in sealed relation to a bore 46 provided in the flange-like element. The flange-like element 35A is provided with an annular plenum 47, generally coaxial with respect to bore 46, and a pair of O-ring seals 48 disposed in straddled relation to the plenum 47 for sealing engagement with the exterior of the port plug 35B. The port plug 35B is provided with a number of injection passageways 49 extending radially from plenum 49 intermediate the O-ring 48 and communicating with perforating passageway 36. Plenum 47 is in fluid communication with an injection conduit 50 which extends from the flange-like element 35A exteriorly of the body 10. Conduit 50 may desirably be provided with a check valve 51 disposed to pass fluids flowing toward plenum 47, but to block any fluid ow from the plenum 47 along the conduit 50. The relationship of the radial injection passageways 49 with respect to perforating passageway 36 will be discussed in greater detail hereinafter.

The lower end of chamber 40 is defined by the top surface of a piston 53` in sealed slidable engagement with= in a cylinder 54 provided in body 10 in communication with chamber 40, but set apart therefrom by an 'inwardly directed flange 55. Piston 53, initially positioned in abutting relation to the flange 55, is adapted to be dieii placed downwardly in cylinder 54 in response to presn sures within chamber 40. Piston 53 is provided with a depending rod portion 56 which extends in sealed slidable engagement within a bore 57 provided in the body 10. Piston 53 and rod 56 are normally maintained in a upward disposition by a shear pin 58. The lower end of conduit 50 communicates with the bore 57 by means of a passageway 59 opening thereinto. Bore 57 also communicates by means of a passageway 60 with an injection conduit 61 which extends externally ot the body 10 to the lower section 70 of the apparatus. The lower end of rod 56 is provided with spaced-apart seals 62 and 63 which, in the normal position of rod 56, served to block uid communication from passageway 60 to the bore 57 and thus constitute a valve normally blocking fluid communication between the conduits 50 and 61. The rod 56 is also provided with an annular groove 64 which, when the rod is displaced downwardly, provides for fluid communication between the conduits 50 arld 6iv when` the rod is actuated downwardly. An Oring seal 63 is provided such that it, together with O-ring seal 63, seals each side of groove 64. With the rod 56 in the upward or normal piston, a space 65 is defined in the lower extremity of bore 57, which space is filled with a liquid, eg., a silicone oil, having a slight amount of compressibility. The space 65 is communicated with cylinder 54 beneath piston 53 by means of a constricted high-resistance iluid flow path 66. The speed of the displacement of piston 53 and rod 56, in response to the pressure chamber 40, is controlled by the rate of displacement of the liquid from space 65 into chamber 54. This accomplishes a desired delay in communicating the conduits 50 and 61 subsequent to the tiring of shaped charge 41. Of course, sufficient space remains in cylinder 54 beneath 53 after its full stroke to receive the entire volume of liquid originally contained in the space 65. When the piston 53 and rod 56 go full stroke in response to pressures in chamber 40, a spring loaded detent 67 provided in the body 1t) engages a groove 67 provided in the rod 56 to maintain the same in an actuated disposition.

Lower section 70 includes a container 71 for housing such treating agents as may be desired for injection into the form-ation zone. The container 71 is in fluid communication at its upper end with conduit 61 such that when a fluid flow path is established to the formation zone is described hereinafter, the treating agent or agents within the container 71 will be injected into the formation under the motivation of the difference in pressure of borehole fluids in excess of the pressure of formation fluids. Although the example of the following description is devoted to the employment of the container 71 so as to serially inject a plurality of treating agents and yet substantially segregate reactive ones of such agents, it will be apparent that the container 71 may be employed to inject a single treating agent into the formation. Further, although the pressure energy of borehole fluid is employed for injection power in the illustrated embodiment, it will be evident that other suitable energy source, such as a propellant gas generator as disclosed by commonly assigned Briggs Patent Number 3,090,436, granted May 21, 1963, as well as by Reynolds Patent Number 3,115,932, granted Dec. 31, 1963, for Apparatus for Consolidating Incompetent Subterranean Formation, may be employed if desired.

When the apparatus is employed for operations, such as sand consolidation, which involves a plurality `of treating agents, the container 71 is provided with a plurality of floating or free pistons for the purpose of segregating the various agents involved. In such a situation, a first free piston 72 is provided within the container to define therein a first fluid compartment 73 at the upper end of the container. This first compartment, in the case of a sand consolidation operation, would contain a binding agent, such as a phenol formaldehyde resin, lfor example, adapted to be hardened after injection into the formation either by passa-ge of time `or by exposure to a subsequently injected catalytic or reactive agent. The compartment 73 may be filled with this first injection agent via a fill port shown closed by a plug 75.

Piston 72 is sealed near its upper end with respect to the walls of the container 71 by means of an O-ring seal 72 so that fluid communication thereacross is blocked. A valve 74, normally biased toward a closed position, is provided in the piston 72. A portion of the valve extends upwardly of the upper surface of piston 72 such that when the same contacts the upper end of the container 71 pursuant t-o traverse of the piston 72, the valve is opened and fluid communication is established through the piston 72. The upper portion of valve 74 is tubular and is co-axially positioned with respect to a passageway 61A connecting the container 71 with the conduit 61, such that when the valve is opened passageway 61A and the bore of the tubular upper end of valve 74 comprise a fluid flow path effectively `by passing compartment 73 and any residual amounts of the first fluid remaining therein. Piston 72 is provided at its lower surface with a thin-walled skirt extension 76 sized to provide an annular fluid flow clearance 77 between the outside of the skirt extension and the interior wall of the container 71. The clearance 77 is communicated at its upper end with the valve 74 by means of passages 78. Piston 72 is also provided with Ian annular recess 79 which, in the initial position of the piston 72, is in communication with a fill port S0, the passages 78 and the interior of the skirt extension 76. The fill port 80 is provided for filling a second compartment 82 with a second treating agent. Compartment 82 is defined between the seal 72 of piston 72 and the upper surface of a second free or floating piston 85 spaced from piston 72 within the container 71. Fill port 8G may be closed by any suitable means such as by the straddle sealed cylindrical sliding closure 81, as shown. In the exampled sand consolidating operation in connection with which the apparatus is being described, the treating agent in chamber 82 is preferably a fluid which is inert as to the phenol formaldehyde resin in chamber 73. Diesel oil has been found to be satisfactory.

A third free floating piston 88 is provided in container 71 spaced from the piston 85 to define therebetween a third compartment 89 adapted to be filled with treating agents by means of a fill port 90, similar to fill port 80.

In the case of the exampled sand consolidating operation, the third chamber 89 carries the third treating agent which is effective to harden the first treating agent previ- -ously injected from chamber 73. In the case of the resin exampled above, the third fluid may be a diesel oil solution of oil-soluble acid.

In addition to the acid-diesel oil solution, the chamber 89 may carry a fourth agent, if it is desired to temporarily plug a perforation after the formation thereabout has been consolidated. This fourth agent may be a low lwater loss gel adapted to form a temporary plug. When such a gel is employed, the perforation will remain plugged for a predetermined time at a given borehole temperature, at which time the gel will break down and, in effect, unplug the perforation. `One example of such a gel having suitable breakdown times at moderate borehole temperature is as follows:

Ammonium persulphate grams 1.2 Guar gum do 14.4 Sodium borate do 1.44 Saturated brine cc 1000 The exampled gel, in being water based, is heavier than Vand immiscible with the diesel oil containing the catalyzing agent, and therefore these two agents may be contained within the same chamber without any substantial mixing.

The lower end `of container 71 is provided with openings 91 admitting borehole fluids therethrough to the underside of piston 88. Since the pistons S8, 85, and 72 are free or floating within the container 71, these pistons, particularly pistons and 88, function primarily as separators of the various fluids within the container 71 and are efficient pressure force transmitters. The result is that the pressure of all the treating agents in container 71 is substantially equal to the hydrostatic pressure of borehole fluids, which pressure is the 'active force employed by the illustrated embodiment in the injecting phase of a formation treatment as `will appear.

The pistons 85 and 88, in functioning as separators with no pressure differential thereacross, may be of the wiper type shown having a plurality of resilient, chevronlike, sealing portions 92 which extend radially thereof to sealingly, but slidably, engage the bore of the container 71. The wiper type pistons are desirable in that they may traverse a discontinuity in the container wall such as filler ports 30 or 90 and still maintain an effective separation of fluids.

Assuming for the moment that fluid communication has been established between the formation fluid and the container 71, the lower section 76 of the apparatus will automatically operate las follows. Since the treatin-g agents within container 71 are at a pressure equal to the hydrostatic pressure of the borehole and since this pressure is effectively higher than the pressure of formation fluids in the normal borehole situation, fluids within the container 71 will flow into the formation under the influence of this effective pressure differential. The first fluid to flow will, of course, be from the first compartment 73, and as this fluid is displaced, the various pistons .and fluids therebelow Iwill be moved upwardly at a rate corresponding to the -rate that chamber 7.3 is being reduced in size by virtue of the flow therefrom. When substantially all of the first fluid has been displaced into the conduit 61, the piston 72 will have contacted the upper end of the container 71 'and valve 74 will have been opened by such contact. This establishes a new flow condition, illustrated in FIG. 2 of the drawing, wherein the second fluid in compartment 82 is flowing through the opened valve 74, passageway 61A, and conduits 61 and 50 into the formation being treated. In this flow condition the second fluid may flow either through the recess 76' defined by the skirt 76 or through the fluid flow clearance 77 and thence via passages 78 to the opened valve 74. As the 'second fluid is displaced ahead of piston 85, the Volume of chamber 82 is reduced by the piston 85 approaching piston 72. This iiow condition is terminated by the piston 85` entering or being swallowed by the recess 76 defined by the thin wall skirt 76. Although the inside diameter of the recess 76' is somewhat smaller th-an the bore of container 71,"piston 85 may enter the same in that the resilient chevron-like sealing 'y portions 92 thereof are compressed -or distorted in the entry. The length lof the recess 76 is, of course, sufficient to completely house the piston 85, so that when the piston 85 has entered the same, the piston 85 is no longer in sealing engagement with the walls of the container. When this occurs, the third fluid in compartment 89 is communicated through the valve 74, passageway 61', and conduits 61 and 50, via annular liow clearance 77 'and the passages 7 8.y Thus it is seen that the entry of the piston 85 into the recess of piston 72 executes a valving function whereby the third and fourth fluids may flow, in that order, into the formation. From the foregoing, it is then seen that once the injection operation is started by the establishment of fluid communication ywith the formation, the lower section 70 of the apparatus will automatically perform a serial injection of the first, second, third and fourth treating fluids in the order, named.

It is generally desirable in apparatus for performing serial injections of different treating agents into a formationzone to minimize any mixing of such agents within the apparatus. This is particularly important with agents that are chemically active with respect to one another, such as the exampled phenol formaldehyde resin and its catalyzing acid, where mixing of the active agents within the apparatus may result in plugging and the aborting of the injection operation. It is in this connection that the exampled inert agent, i.e., diesel oil, is employed. Within the container 71 it serves to more effectively segregate the first and third agents by physical spacing within the container 71'. During the injection cycle, the inert of second agent in compartment 72 takes substantially the same [flowr path through the apparatus as the rst agent andy serves to cleanse the dow path of residual quantities of the tirst agent. The effectiveness of this cleansing action is enhanced by a fluid flow velocity over the path which gives rise to a scouring action tendingk to remove any residual films from the wall of the iiow path. By way of example, a flow area in conduitl 50 of .049 square inch has ygiven satisfactory results in scouring the exampled resin at injection rates which have been experienced.

Aperforation establishingr uid communication be-A tween a well bore and the adjacent earth formation should present a large maximized flow area to uid entering the perforation from the formation, or the borehole, in order that the perforation may Vhave a maximized flow capacity with `any given differential pressure thereacross. This type of perforation, i.e., a clean perforation, is believed particularly desirable in formations of varying degrees of incompetence and which are to be 4treated by injection of consolidating or binding agents. kThe reason for this is that the natural permeability of the formation will be reduced within a volume of consolidated material about the perforation, but provided the perforation has a maxilrnized ow area, the overall effect on perforation flow is minimized.

Although a typical well bore perforation may have an adequate depth ofV penetration it is typically initially filled wih impacted with detritus (both from the formation and from the perforator) to such an extent that an adequate or maximized flow area is not initially provided. Such an impacted perforation may be subsequently cleaned up by productive flow under some conditions, but a perforation through which a consolidation treatment is immediately performed, if not initially clean with a maximized iow area, will never become so because the impacted detritus will be consolidated along with the formation.

Referring to FGURE 6, a desirable perforation 45' through a casing wall 14', a cement sheath 15 and the formation therebeyond is shown in the process of being formed by a jet 4t2 emanating from a shaped charge 41', together with How-indicating arrows illustrating a flow condition believed effective in producing such a clean perforation. In the illustration, flow of formation iiuid tow-ard and into the perforation is indicated by arrows with open or unshaded arrowheads. Within the perforation, ow of formation fluids admixed with perforation detritus entrained therein is illustrated by arrows having shaded arrowheads. These shaded arrows converge and .pass through the perforation in the casing wall 14' where such converged flow is indicated by a vector 44 directed toward the shaped charge 41' which produced the jet 42. Although it is believed that such illustrated flows take place commitantly with the penetration of the jet 42 under certain discovered conditions, it is known that when the perforation is made under these conditions, a clean perforation 45' -of m-aximized iiow area is produced. The conditions which dependably give rise to a clean perforation are those wherein the following relationship of borehole and formation iiuid parameters obtains.

[Heffi-Tl where Perforating conditions wherein the above relationship obtains are assured through the control of the pressure and viscosity of uids within chamber 40 during the perforating process. To this end, chamber 40 is preferably filled with a low pressure gas, say air and atmospheric pressure, and is of a volume such that it m-ay contain any gases evolving from the shaped charge 41, when the same is fired, ata pressure suitably low for the relationship to obtain. By way of example, it has been -found experimentally that if RDX is employed as the primary explosive, and if chamber 4G is of a size providing approximately 5 cubic inches of atmospheric pressure gas volume per gram of RDX employed, then the gas generated upon the tiring of the shaped charge will produce a pressure within the chamber on the order of 30() hundred pounds per square inch. This pressure value, together with the kinematic viscosity value of the cornbustion products, is appropriate to produce a clean perforation under many formation borehole fluid situations. Of course, the total volume of the chamber 40 should be adequate to receive all the detritus and formation fluid comprising the counter flow.

With further reference to FIGURE 3 the counter flow vector 44' (discussed in relation to FIGURE 6) is shown in the relation it bears to the apparatus portion illustrated. Although the perforating charge 41 is shown unired and the perforation has yet to be made, the relationship illustrated shows the counter flow vector 44 directed along the center line of perforating passageway 36 and the axis of the charge `41. It will be noted that the injection passageways 49 are disposed in perpendicular relation to the counter iiow vector 44', Vwhich relationship is effective to minimize entry of detritus carried by the counter ow into the passageways 49. This has been found to be of considerable importance in providing a reliable field-worthy tool, inasmuch as entry of detritus in the injection system may tend to plug the same and abort an injection operation.

FIGURE 4 shows an alternate construction of that portion of the apparatus illustrated in FIG. 3. The components of FIG. 4 are similar, for the most part, to those in FIG. 3 and carry similar reference numerals differentiated by prime marks. FIG. 4 provides another embodiment wherein detritus carried by the counter ow vector 44 (is substantially prevented from entering the injection passageways 49. In this embodiment it will be noted that the port plug 35B Ihas no communication with the injection system, but, rather, the injection passageways 49' are disposed in parallel relation to the counter flow vector 44 such that no component of such vector exicts along the injection passageways which would tend to drive particles carried by the counter `flow thereinto.

FIGURE illustrates a modified apparatus portion generally similar to those illustrated in lFIGS. 3 and 4. Because of the similarity to FIGS. 3 and 4, c-ommon reference numerals with delineating prime markings are employed. The embodiment of FIG. 5 illustrates still another arrangement of the injection passagew-ays 49 with respect to the counter flow vector 44', the perforating passageway 36 and the jet charge axis. In this arrangement, injection passageways 49" are inclined at an angle a with respect -to the vector 44' and the flow passageway. This angular disposition is such that if the counter ow vector 44 is resolved into components along 44a and perpendicular 44b to the injection passageways 49, the component 44a along the passageways 49 will be directed toward the perf-orating passageway 36". With this sort of disposition, the inuence of the component 44a along the injection passageway 49 will tend to purge the same to `accomplish a more positive way of preventing detritus from the counter ow from entering the injection system.

With respect to the embodiments of FIGURES 3, 4 and 5, it will be seen that the injection passages 49, 49', 49" are disposed with respect to the counter flow vector 44 such that no substantial component of this vector exists which would tend to cause detritus carried by the counter ow 44 to enter the injection system of the apparatus.

Operation In carrying out a treating operation with the present apparatus and method, apparatus would be chosen having a chamber 4t) of such volume that, after accommodating the gases from the explosive employed, the pressure PW' in the chamber will be of sufficiently low value in relation to the kinematic viscosity uw of `the combustion products, as well as in relation to the pressure and kinematic viscosity of formation fluids (previously obtained by formation sampling procedures, for example) to satisfy the above discussed relationship defining perforating conditions whi'ch will yield a clean perforation of maximized flow area.

Having selected suitable apparatus, such apparatus would be lowered into the borehole and borehole fiuid environment (usually provided in the borehole for purposes of pressure control and the like) by means of wireline 11 to a depth such that the annular seal element 34 is located adjacent the formation zone intended for perforation and treatment. When so positioned, a suitable electrical signal is applied to the conductor 12 of the wireline to initiate operation of the pressure generator 22 which, as previously brought out, supplies hydraulic uid at super-hydrostatic pressure to force the plungers 29 of upper and lower actuator elements laterally of the body 10. This results in the annular seal element 34 being thrust into sealing engagement with the wall of the casing to isolate .a part thereof from the general borehole uid environment and to anchor the body l@ against displacements in the course of the operation. This anchoring is obtained by virtue of the hardened serrations 31 on the end `of plungers 29 cutting into the wall of the casing 14. It will be appreciated that if the annular seal element 34 should shift with respect to `the perforation to be formed through the casing, the uid communication between the apparatus and the formation through the casing perforation would be lost and any attempt at injection of treating agents into the formation would be aborted.

After the apparatus has been thus placed in sealed anchored engagement within the borehole, the shaped charge 41 may be fired to the agency of the usual Primacord and bla-sting cap arrangement which is, in 'turn, activated by a second electrical signal communicated from the earths surface over the wireline. The jet ensuing from the firing of the shaped charge and making the perforation also establishes fluid communication between the perforation in the formation and the chamber 40 so that counter flow 44' ensues to produce the clean perforation desired.

Shock wave forces produced by the explosive of the charge 41 upon firing, act on the upper surface of the piston 53 to displace the same and rod 56 downwardly to shear the shear pin 58. The small compressibility of the uid in spa-ce permits a slight downward movement to accomplish shearing of shear pin.

The counter flow int-o chamber 40 increases the pressure therein until it is equal to the pressure of formation fluids, whereupon the counter flow ceases. The pressure in chamber 4) acts on 4the top of piston 53 and urges the same downwardly at a rate limited by the rate fluid flow through the restricted passageway 66 into the space provided below the piston 53. This limitation on rate provides a time delay on .the order of one to four seconds between the firing of the charge and the communication of passages 59 and 60 pursuant to motion of groove 64 into bridging, uid conducting relation between the ends of passageways 59 and 60. Upon this happening, fluid communication is established between the formation and the container 71, whereupon treating agents in the container will be forced therefrom into the formation by virtue of the pressure differential toward the formation.

Assuming a sand consolidating Ioperation is performed with treating agents previously exampled, the lower section 70 would operate as previously indicated. First, the phenol formaldehyde resin in chamber 73 would be injected into the perforation and formation thereabout. Next, the inert diesel oil would be injected from chamber 8-2 to drive or displace the resin from the perforation into the formation and, further, to over displace the resin within the formation to remove any excess as may occupy space between the grains of sand that constitute the formation, a lm of the rst fluid being retained about the sand grains by capillary forces. Next, the third or catalyzing agent, i.e., the acid solution is injected to overdrive the second fluid whereupon the catalyst makes contact with the plastic film previously established about the formation particles. This contact operates to harden the plastic film and bind the sand grains together and impart new strength to the unconsolidated material about the perforation. Since limited quantities of material may be contained in 'wireline apparatus, it would be evident that only limited volurnes of formation may be consolidated in a given operation with such apparatus. Nevertheless, such limited quantities are affective to produce an effective screen or lter about the perforation adjacent the well bore wall with sufficient permeability to pass the desired fluids for production but to exclude unconsolidated formation particles.

If it is desired to perform other perforating and consolidating operations within the same unconsolidated zone, it may be desirable to temporarily plug the first perforation in order that pressures of the borehole will not be communicated to the productive zone. In this event, a fourth agent, such as the previously exampled gel, may be provided in the third chamber 89 and placed in the perforation following the injection of the third agent. The gel, when placed in the perforation, is effective to block communication of borehole fluid pressure to the -formation for a predetermined time, depending on the particular gel selected. If the subsequent consolidating operation is performed within the predetermined time, it may be carried out in the same manner as the first consolidating operation, i.e., without being inuenced by another adjacent perforation.

After the injection operation has been completed, the apparatus may be withdrawn from the borehole upon the retraction of actuator elements y24 and 25. This is accomplished by transmitting `a suitable signal to the pressure generator 22,Whereupon the pressure in the hydraulic system is dropped to a pressure ,less than the hydro- .static pressure of borehole fluids, so that the hydrostatic pressure of the borehole forces the plungers 29 of the actuat-ors back to a retracted disposition in the body of the apparatus.

Thus, it has been seen that the apparatus and method of the invention provides an efficient and economical solution to problems associated with the treatment of formations adjacent Ia perforation. It has further been seen, in connection with the exampled treatment, that the method and apparatus of the present invention enables reliable sand consolidating treatment of formations wherefrom sand is being produced or is likely to be.

As various changes may be made in the method and constructions herein described ywithout departing from' the Aspirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that Vall matters herein are to be interpreted as illustrative and not in any limiting sense.

What is claimed is:

1. Wireline .apparatus for treating a permeable earth formationzone containing a formation fluid under pressure and traversed by a cased borehole containing `a column of fluid extending upwardly of said zone providing a hydrostatic pressure environment Within said casing greater than the pressure of formation fluid, said apparatus comprising: a body adapted to be lowered within said borehole by means of a wireline; perforator means including k,explosive -material disposed insaid body for perforating said casing along a predetermined axis to establish fluid communicationywith the formation therebeyond when said explosive material is fired; a compartment in said body providing .a volume of low pressure gas of a size to contain any gases evolving from said y explosive material when fired at a pressure less than the fluidchamber intermediate said first-and second floating t pistons, and a third floating piston defining .a third fluid chamber intermediate said second and thirdfloating pistons, all said floating pistons being lin sealed slidable engagement with the wall Iof said container and all said chamber containing injection fluid; means on said body forming a passage connecting said first fluid chamber and said space to admit injection fluid to said isolated area; means including a valve on said first floating pist-on for fluidly connecting said second chamber to said passage responsive to predetermined travel of said first floating piston; means on said first piston for unsealing said second piston in response to predetermined travel thereof whereby the injection fluid in said third'fluid chamber is communicated past said second piston and then via said valve and passage to said isolated area, the arrangement of said chambers and pistons providing for sequential injection of injection fluid from saidfirst, second `and third fluid chambers into said formation via. said fluid communioa-tiion in the order stated in response to movement of said third floating piston; and means for applying lforce to said thirdV floating piston for moving the same.

- 2."A device for injecting fluids into an earth formation adjacent the walls of a borehole comprising: a body adapted to` be lowered into a borehole; sealing means mounted on said body and adapted to define an isolated area of borehole wall and establish communication therewith when urged thereagainst; means connected to said body for uring said sealing means into engagement with the wall of the borehole; said body including a container with a first floating piston therein defining a first chamber, a second floating piston therein defining a second fluid chamber intermediate said first and second floating pistons, and a third floating piston defining a third fluid chamber intermediate said second and third floating pistons, all said floating pistons being in sealed slidable engagement with the walls of said containerV and all said chambers containing injection fluid; means on said body forming a passage connecting said first fluid chamber and said sealing means to admit injection fluid to said isolated area; means including a valve on said first floating piston for fluidly connecting said second chamber to said passage responsive tio predetermined travel of said first floating piston; means on said first piston for unsealing said second piston in response to predetermined travel thereof whereby the injection fluid in said chamber is communicated past said second piston and thence Via said valve and passage to said isolated area, the arrangement of said chambers and pistons providing for sequential injection of injection fluid from lsaid first, second and third chambers into said formation in the order stated in response to movement of said third floating piston; and means for applying force to said third floating piston for moving the same.

3. A device for injecting fluids into an earth formation adjacent the wall yof a borehole comprising: a body adapted to be -lowered in the borehole; sealing means mounted on said body and adapted to define an isolated area of borehole wall and establish communication therewith when urged thereiagainst; means connected to said body for urging said sealing means into engagement with the wall of the borehole; said body including a container having a first floating piston therein defining a first fluid chamber, a second floating piston of resilient material therein defining a second fluid chamber intermediate said first and second floating pistons, and a third floating piston defining a third fluid chamber intermediate s-aid second and third floating pistons, all said floating pistons being in sealed slidable 'engagement with the Walls of said container and all of said chambers containing injection fluid; means on said body forming a passage connecting said first fluid chamber and said sealing means to admit injection fluid to said isolated area; means including a valve on said first floating piston for fluidly connecting said second chamber and injection fluid therein to said passage responsive to predetermined travel of said first floating piston; said first floating piston including a receptiacle providing annular clearance with said container, said receptacle adapted to swallow said second floating piston upon a predetermined travel thereof, whereupon the fluid in said third chamber is communicated past said second piston via said annular clearance and thence via said valve and passageway to said isolated area, the arrangement of said chambers land pistons providing for sequential injection of injection fluid from said first, second and third chambers into said formation in the order stated in response to movement of said third floating piston; and means for applying force to said third floating piston for moving the same.

4. Wireline apparatus for 4treating a permeable earth formation zone traversed by a borehole including a casing comprising: a body adapted to be lowered within said borehole by a means of a wireline; perforator means including explosive material disposed in said body for perforating said casing along a predetermined axis to establish fluid communication With the formation therebeyond when said explosive material is fired; sealing means on said body for isolating said fluid communication from the general environment of said borehole by sealing off an area of casing wall when urged thereagainst, said sealing means defining With said body and casing wall a space through which said perforator means operates in establishing said fluid communication; means on said body for urging said sealing means into engagement With said casing Wall; a chamber in said body containing a fluid for injection into said formation; a fluid flow passageway connecting with said chamber and terminating in fiuid communication with said space; a check valve in said passageway adjacent said termination permitting fluid flow in said passageway from said chamber to said space but blocking iiuid fiow in the opposite direction; and means for displacing said injection fluid from said chamber via said passageway, check valve, space and perforation into said formation, a second chamber containing said explosive charge and being a receptacle for detritus developed when said casing is perforated by firing of said explosive material, said passageway being exclusive of said second chamber such that said injection uid is prevented from flowing in a direction and in a path which extends from said second chamber into said space.

5. Apparatus as set forth in claim 4 including normally closed valve means in said passageway, and means operated by -pressure developed when said explosive material is fired for opening said valve means.

6. Wireline apparatus for treating a permeable earth formation Zone traversed by a borehole including a casing comprising: a body adapted to be lowered Within a borehole by means of a wireline; perforator means including explosive material disposed in said body for perforating said casing along a first axis to establish fluid communication with formation beyond said casing; a cornpartment in said body housing said explosive material; sealing means on said body for isolating said axis from the borehole generally and defining with said body and casing wall a space traversed by said axis; means on said body for urging said sealing means into engagement with the wall of said casing, a chamber in said body containing a uid for injection into said formation; a fiuid flow conduit extending from said chamber and entering said space along a second axis; and means for displacing said injection fluid from said chamber via said conduit along said second axis into said space and thence via said perforation into said formation, said second axis being disposed with respect to said first axis such that any substantial component of a vector representative of iiuid flow along said first axis toward said compartment which exists along said second axis is directed toward said first axis.

7. Wireline apparatus for treating a permeable earth formation zone containing a formation fiuid under pressure and traversed by a cased borehole containing a column of fiuid extending upwardly of said zone providing an environment of hydrostatic pressure within said casing greater than the pressure of formation fluid comprising: a body adapted to be lowered within the borehole by a means of a wireline; a compartment in said body containing a gas at a pressure less than the pressure of formation liuid; perforator means including explosive material in said compartment disposed to perforate said casing and establish fiuid communication with formation therebeyond along a first axis defining a path for purge flow of formation fiuid from said perforation toward said compartment when said fiuid communication is established; means on said body for sealing off an area of casing wall when urged thereagainst, the last-mentioned means defining, with said body and casing wall, a space traversed by said first axis; means on said body for urging the lastmentioned means into engagement with the casing wall; a chamber in said body containing a fluid for injection into said formation; an injection fiow path extending from said chamber and entering said space along a second axis; means for displacing said injection fluid along said injection flow path and second axis into said space and thence via said perforation into said formation; said second axis being disposed with respect to said first axis such that any component of a vector representative of said formation fiuid flow along said first axis which exists along said second axis is directed toward said first axis.

8. Wireline apparatus for treating a permeable earth formation Zone containing a formation fiuid under pressure and traversed by a cased borehole containing a column of tiuid extending upwardly of said zone providing an environment of hydrostatic pressure within said casing greater than the pressure of formation fiuid comprising: a body adapted to be lowered within the borehole by a means of a wireline; a compartment in said body containing a gas at a pressure less than the pressure of formation fluid; perforator means including explosive material in said compartment disposed to perforate said casing and establish liuid communication with formation therebeyond along a first axis defining a path for purge fioW of formation fluid from said perforation toward said compartment when said fluid communication is established; means on said body for sealing off an area of casing wall when urged thereagainst, the last-mentioned means defining with said body and casing wall a space traversed by said first axis; means on said body for urging the lastmentioned means into engagement with the casing wall; a chamber in said body containing a fiuid for injection into said formation; an injection fiow path extending from said chamber and entering said space alonga second axis; means for displacing said injection fiuid along said injection flow path and second axis into said space and thence via said perforation into said formation; the disposition of said second axis with respect to said first axis being such that no substantial component of a vector representative of said formation fluid fiow along said first axis exists, which would tend to cause detritus carried by said purge fiow to enter said injection flow path.

9. Wireline apparatus for treating a permeable earth formation zone containing a formation fluid under pressure and traversed by a cased borehole containing a column of fluid extending upwardly of said zone providing an environment of hydrostatic pressure within said casing greater than the pressure of formation fluid comprising: a body adapted to be lowered within the borehole by a means of a wireline; a compartment in said body containing a gas at a pressure less than the pressure of formation fiuid; perforator means including explosive material in said compartment disposed to perforate said casing and establish fluid communication with formation therebeyond along a first axis defining a path for purge flow of formation fluid from said perforation toward said compartment when said fiuid communication is established; means on said body for sealing off an area of casing wall when urged thereagainst, the last-mentioned means defining with said body and casing wall a space traversed by said first axis; means on said body for urging the last-mentioned means into engagement with the casing wall; a chamber in said body containing a fluid for injection into said formation; an injection fluid iiow path extending from said chamber and entering said space along a second axis; means for displacing said injection fiuid along said injection fluid fiow path and second axis into said space and thence via said perforation into said formation; said second axis being disposed at an angle re-entrant with respect to the direction of said purge fiow along said first axis, said angle having a magnitude within a range including ninety degrees.

References Cited by the Examiner UNITED STATES PATENTS 2,582,719 1/1952 Ramsey 166-100 X 3,010,517 11/1961 Lanmon 175-4.52 3,022,826 2/1962 Kisling 166-100 3,115,932 12/1963 Reynolds 175-4.52 3,153,449 10/1964 Lebourg 166-100 X 3,174,547 3/1965 Fields 175-4.52 3,217,804 11/1965 Peter 166--63 CHARLES E. OCONNELL, Primary Examiner. JACOB L. NACKENOFF, Examiner.

D. H. BROWN, Assistant Examiner. 

4. WIRELINE APPARATUS FOR TREATING A PERMEABLE EARTH FORMATION ZONE TRAVERSED BY A BOREHOLE INCLUDING A CASING COMPRISING: A BODY ADAPTED TO BE LOWERED WITHIN SAID BOREHOLE BY A MEANS OF A WIRELINE; PERFORATOR MEANS INCLUDING EXPLOSIVE MATERIAL DISPOSED IN SAID BODY FOR PERFORATING SAID CASING ALONG A PREDETERMINED AXIS TO ESTABLISH FLUID COMMUNICATION WITH THE FORMATION THEREBEYOND WHEN SAID EXPLOSIVE MATERIAL IS FIRED; SEALING MEANS ON SAID BODY FOR ISOLATING SAID FLUID COMMUNICATION FROM THE GENERAL ENVIRONMENT OF SAID BOREHOLE BY SEALING OFF AN AREA OF CASING WALL WHEN URGED THEREAGAINST, SAID SEALING MEANS DEFINING WITH SAID BODY AND CASING WALL A SPACE THROUGH WHICH SAID PERFORATOR MEANS OPERATES IN ESTABLISHING SAID FLUID COMMUNICATION; MEANS ON SAID BODY FOR URGING SAID SEALING MEANS INTO ENGAGEMENT WITH SAID CASING WALL; A CHAMBER IN SAID BODY CONTAINING A FLUID FOR INJECTION INTO SAID FORMATION; A FLUID FLOW PASSAGEWAY CONNECTING WITH SAID CHAMBER AND TERMINATING IN FLUID COMMUNICATION WITH SAID SPACE; A CHECK VALVE IN SAID PASSAGEWAY ADJACENT SAID TERMINATION PERMITTING FLUID FLOW IN SAID PASSAGEWAY FROM SAID CHAMBER TO SAID SPACE BUT BLOCKING FLUID FLOW IN THE OPPOSITE DIRECTION; AND MEANS FOR DISPLACING SAID INJECTION FLUID FROM SAID CHAMBER VIA SAID PASSAGEWAY, CHECK VALVE, SPACE AND PERFORATION INTO SAID FORMATION, A SECOND CHAMBER CONTAINING SAID EXPLOSIVE CHARGE AND BEING A RECEPTACLE FOR DETRITUS DEVELOPED WHEN SAID CASING IS PERFORATED BY FIRING OF SAID EXPLOSIVE MATERIAL, SAID PASSAGEWAY BEING EXCLUSIVE OF SAID SECOND CHAMBER SUCH THAT SAID INJECTION FLUID IS PREVENTED FROM FLOWING IN A DIRECTION AND IN A PATH WHICH EXTENDS FROM SAID SECOND CHAMBER INTO SAID SPACE. 